Why Nepal has a problem with India-China trade through Lipulekh Pass

New Delhi has strongly reacted after Nepal took objection to the resumption of border trade between India and China through Lipulekh Pass, on the border between Uttarakhand and Tibet. Kathmandu claims Lipulekh, Limpiyadhura and Kalapani as part of its territory. But why is there a dispute over these areas controlled by India?

Explainers